The drying process is traditionally an atmospherical, closed-cycle configuration. The wet product is fed into the drier by a dosing unit suitably fabricated for the physical characteristics of the product being treated. When introduced into the drier, the product undergoes the rotor centrifugal action which causes it to move forward in a thin dynamic and turbulent layer along the stator hot wall. The forward movement speed depends on the blade profile and, most of all, on the angle of incidence of the rotation plane to the translation axis. The blades have adjustable pitch and are extensible; it is possible, therefore, to optimize their position depending on the characteristics of the material to be treated and on the highest yield obtainable. The necessary thermal energy is yielded by the stator jacket, where a hot heat transfer fluid, generated by a central heating unit, is circulated. Vapours and circuit air are conveyed to a jet condensing unit, where vapours are condensed by the circulating fluid and discharged automatically while the air, heated, is re-circulated into the drier, thus contributing to create closed-cycle conditions. The air vents are automatically drained, deodorized, if necessary, and conveyed to the heater mixed with the combustion air.